I have a Prodectech Scorpion 27 which just went out of warranty, and the motor died. The bicycle would be hard to replace, even if I wanted to replace the whole thing. It weighs in at 40 lbs, including a Tubus ultralight pannier system. The bicycle is a "custom" made aluminum frame, with high-quality lightweight components, all designed to come in at 39 lbs. The only mistake Prodecotech made was in choosing a 250 W motor system that is not robust (Keyde). When is was working it was great, very quiet. I don't care about throttle. I like to pedal, just want a little help.

So looking around, it's a jungle out there. The all-in-one wheel systems are obviously not really good in practice. I find systems like Dillenger, which is almost good, but has that whimsical cadence sensor that does not attach solidly. Others are too heavy. I am not heavy (165 lb), and I would like a reasonable range while keeping to a max of about 7.5 kilograms for the system.

Thanks in advance. Please don't reply that weight is overrated. I rode my Prodecotech from Maryland to New York, going about 50mi per day, in early Spring. In the wilds of Pennsylvania they don't have Uber. One day it was snow and howling wind. If your battery dies on a 70 lb bike (including your gear), how far do you think you would get? Don't forget hills. I want to be able to at least limp to some kind of shelter, and I am not a young person. So I am weight-conscious.

If the moderator could move this thread to "E-Bike General Discussion," would be nice. It was my first time on the site and I thought it was for ebikes. I also have a solar array (4x350W) I built in my yard (roof won't work and too many trees). I ran 110 feet of 8 gauge cable from it to get back to the house, mainly to power my mini-split heat pump. More about that in another thread.

Welcome to the forum.
Those integrated Keyde are interesting, and friction drive is going to be quiet, but i wouldn't call it robust. I don't know of any other hub motor in this size range with an internal controller. The only direct replacement is going to be another Integrated Keyde, and they only make it in 250w.

But if you are willing to use an external controller, then there are a world of better options. The Q100CST would be a good light alternative in the 350w range, so it will be stouter. Bafang makes a 350w CST motor that would also be a good option . On the upper end of the scale are the eZee motors.

The only mistake Prodecotech made was in choosing a 250 W motor system that is not robust (Keyde). When is was working it was great, very quiet.

If the only problem is the motor, and you liked the way it worked before, I'd recommend just replacing the motor itself with a similar new one, such as the Q series, or small Bafang CST, etc. If you can measure the spoke flange diameter and spacing of your existing motor, and get those measurements of other similar motors, if they are the same then you can simply replace the actual hubmotor and not the whole wheel, relacing the spokes and rim onto the new motor.

ALternately, you can get small motors from places like Grin Tech http://ebikes.ca , etc., already built into wheels.

I'd recommend verifying with whoever you buy from that the no-load RPM of the motor you're getting is similar to that of the one you're replacing.

Either way you can transplant the connector from the old motor to the new one, and if the old is sensorless then you don't even need to worry aobut anything but the three larger (phase) wires.

If the controller is integrated into the motor, then it might be the controller itself that's failed, not the motor, and in that case you can probably get an external controller that does the same functions, and just run the phase wires out to the new controller.

Then you will be back up and running with similar assist that you had before.